Chuck for percussion-drills.



L. L. SCOTT.

CHUCK FOR PERCUSSION DRILLS.

APPLICATION FILED AUG. 8, 1914- Patented May 16, 1916.

INVENTOR souri, have invented 26 cushion 85 specification UNITED STATES F TE g3 LEWIS Li SGO TT, OF ST. LOUIS, M ISSOURI.

annex iron recession-mums.

Specification of'Lett'ers Patent.

atented May 1 6, 191%.

Application filed August a, 1914f seriaimssam.

and use the same, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to'improveznents in that class of drill chucks shown and de scribed in my prior United Stateslatent No.

1,058,268, granted April,8,l91$

In the forznof chuck described in my prior patent above referred to, I have found it necessary, in practice, to provide a soring bufi'er to cushionthe blow on the dril bit when the said bit reaches its extreme limit of, travel.

One of the objects of my present invention I is to obviate the necessity ofsuch a spring and. this result I obtain by providing theforward endof thecylinder with an air chamber forming a cushion for the piston and, at the same time, allowingthe movement between atheydrillbit and the 90 chuck to be such that the drill bit may move entirely out of the path of thepiston.

My invention alsoconsists in certain other novel features and details of construction, all of which are described in the following up ended hereto.

n the accompanying drawings, which illustrate one form of chuck made in accordonce with my invention, Figurel isa vertical longitudinal section; and FigQQ is across section taken onthelineA A ofFig. 1.

Like marks of reference refer to similar parts in both views of the drawings 5 represents e 'cylinder COIltiLlIrll'lg an outer floating piston fi and aninner piston. 7 which is connected by itman rods 8 with a crank shaft 9 mounted in the lower end of the cylinder 5.. The crank shaft 9 is preferably provided with a-fly wheel 10. Garriedb 1111 1 extension 11 of the cylinder 5 is a chucr 12 adapted to receive the shankof the'dnll' bit. 13.- The chuck 12 is held in: position" by a cap'lsecuredby screws 15. he chliCk lZ is provided with a worm wheel L6 engaging andpointed out in the claims shaft 9 by shown as it forms invention. bears against a block 19 carried by arod 20 which, in practice, forms an extension-of the drill bit and is struck by the lower face of the outer floating piston 6. The drilihit lii may be provided with a centralopening 211 13;

communicating with a supply pipe for removing the drillin-gs from the hoie' formed by the bit. erally through it a locking bar 24*, best shown in Fig. 2. This locking her '24 is provided with a notch 25 which is adapted to allow the drill bit 13 to move into and out of position when the said notch is brought in order to hold the locking bar 24 in position, Iprointo alinement with the drill bit.

vide a ball 26 seating in a recess in the said bar and normally held in position by means of a spring 27.

In order to allow of longitudinal move-' ment between the drill bit and the chuck, I provide the drill bit 13 with a slot 28. This slot 28 is of such length as to allow the drill bit to move downward to such an extent any suitable'gearing which is not" no part of the present The rear end of the drill-bit 13 The chuck 12 has passing lat- 1 that the rear end of the rod 20 will not be. struck by the end of the. piston 6 when the drill bit reaches its extreme lower position.

I also provide the cylinder 5 with {an ex tension 29 at lts lower End,'VthlClhGXiiQl'lSlOil forms an air chamber to cushion the floating piston 6 whenthe said piston reachesitsew treme downward movement. The use of this,-

air chamber, together with a slot 28, enables me to dispense with any cushioning meansfor the drill bit.

mechanical In order to allow the air to enter'bet ween the upper end of 'the internal piston 71 and the external floating piston, 6, I rovide o. valve30 in the rear face of the saic. external;

piston, which valve is controlled by a. s it able sprin 31. Air is allowed to enter the 31 i interior 0 the inner piston 7 thronghfen" opening 32, which. opening 32 is adapted to.

be brought into alinement with a. slot 33;. formed n the oi' ter piston'ti and a siot 34. a formed inthe cylinder 5. 1 Air is alien/edv to. enter between the lower endof the interior .piston' 7 and the-outer piston 6 through ports 35 adapted to communicate with the said slot 34.

36 is a passageway for the fuel from the 'lower'end of the cylinder 5'. Fuel is adapted its .to enter the "lower end of the cylinder 5 with .a' worm 17 mounted ona cross shaft 18.

' throughaport 37.

' This cross shaft isdriyen from-the crank 815s a discharge port for. Carrying the rntngases from the cylinder 5. flheoperation of my engine is as follows:

posing the parts to be substantially in" "position shown in Fig. 2 and a charge. 'f iconipressedgas to be contained between mpperend of the outer piston 6 and the gfhead of the; cylinder 5. The said charge is "ignited by any suitable igniting mechanism. not shown); Thepistons 6 and 7 will then "drivendorward until the piston Gstrikes met the end of the rod 20, thus deliverfthef orce'of thecharge against the drill Lin-the? normal operationof the ma-v une,this will take place before the iniorfpiston has reached the; end-of its As this piston is connected by'means rats rods 8 with the crank shaft, 9, re piston willv continue its travel for time distance after the outer piston .6 hasn pped by contact with the rod 20. heinterior piston 7 moves forward, air

be allowed. to enter into the space beiston fithrough thevalve 30. .Inaselli as thisvalve 3G is placed in the end of the piston, air will'be allowed to i ter between the two pistonswhen only a ry slight movement takes; place.- This "uld not be accomplished inthe construc-.. ionshown in applicants prior-patent, above red to, w-here the port for allowing the VT fi-to enter between the two pistons is an: ranged in .outer piston'at some distance v, its return movement, the air between the" ftwozpistons Will form a cushion to force the outer piston back againstthe charge con "trained between the. end of the outer piston and the head of the cylinder in case the drill=' is fed down to: its extremellimit of travel. The'outerpiston (Lin its forward movement, 7will enter theairchamber 29,fo rmingf,an 1 extension of the-cylinder 5, and theefle'ct I otsiich air chamberwill be to cushion the blow andthus avoidinjury to'the mechashown in Fig. 2, may be provided a nthe upper end of the said piston-and with a chuck provided with a longitudinal g 4 {locking bar, L n: Bymeans ofthe'locking bar 24,: the

to prev'ent the locking bar 24 being entirely removed from the chuck.

,ed toibe engaged by the said locking bar.

2. In a percussion drill, the combination with a chuck provided with a longitudinal passage for the drill bit, of a locking. bar

for limiting the movement of the drill, said locking barslid-ing laterally in said chuck and providedat one endwith a notch to allow the insertion and removal of the drill bit, means for holding -said locking bar'in positiomand a drill bit provided with a slot adapted to engage with said locking bar. i a 3. In a percussion drill, the combination passage .for the drill bit, of a locking bar sliding laterally insaid chuck for limiting the movement of the drill, said locking bar being provided at one end with 'a notchto allow the insertion and removal of the drill 'ibit, means for yieldingly holding said looking bar'in position, and a drill bit provided 7 with .a slot-adapted to engage with said. locking bar. I 35" from its end. it henthe inner piston begins 4-, In a percussion drill, the combination with-a-chuck providedwith a longitudinal passage for the drill bit, of a locking bar sliding-"laterally in said chuck for limiting the movement of thefdrilhsaid' locking bar being provided at oneend with a notch to allow the lnsertion and removal of the drill bit, a spring detent engaging with one side'of said locking bar for yieldingly holding it -in position, a drill bit provided with'a' slot adapted to engage'with. said In testimony whereof, I hereunto set niy hand and affixed my seal in the pres 

